Annuals by definition are plants that survive just one growing season. Some annuals are actually perennials or even woody shrubs in other parts of the country but, because they are not frost tolerant, cannot survive our winters. Many gardeners try to avoid the inevitable by overwintering some of their prized annuals indoors. Some annuals overwinter easier than others. For example, many gardeners successfully overwinter their geraniums from year to year. See the September 16, 1994 issue of HHPN for instructions on the different ways to overwinter geraniums.
Another popular annual, impatiens, can also be grown indoors. Take stem cuttings from desired varieties in late summer. Root cuttings in perlite or coarse sand. After rooting, pot them into well-drained potting media. Because light duration is lacking during the winter months, place the potted plants in a bright, sunny location. If you do not have optimal light conditions, artificial lighting may be the answer. Impatiens that have spent the summer in containers can be pinched back leaving one-third of their original height and brought indoors. This also applies for the popular New Guinea impatiens.
Fibrous begonias also make attractive interior plants. Because they have a fibrous root system, they can easily be dug from the ground and placed in containers for the winter. Like the impatiens, trim the tops back to about one-third of their original height. Dwarf varieties are the most successful for indoor use.
Browallia has become popular for hanging baskets. It too can be overwintered similar to impatiens and begonia. Additional annuals that can be propagated from stem cuttings include coleus, Joseph's-coat, polka-dot plant, nierembergia, verbena, and cigar flower. Ornamental peppers, eggplant, and even kale can be grown in containers indoors.
Fuchsia, like geraniums, can be overwintered in different ways. Cuttings can be taken from plants in late summer and rooted. The rooted cuttings are potted up and then ts placed in a bright sunny location and treated as foliage plants throughout the winter. Another method is to keep the plant over in a dormant state. Before a hard frost in the fall, place the containerized plant in a location that can be maintained about 40 to 50 F. Water the plant once a month to keep the wood from drying. In February, prune back to the old wood and place in a sunny location. Hard pruning will induce branching which in turn will produce abundant flowers during the summer months. These same methods can also be used to carry lantana through the winter as well.
Many gardeners grow plants like paper flower (Bougainvillea), glory bower (Clerodendrum), and mandevilla (Dipladenia), in hanging baskets or other containers during the summer. They can be brought indoors for the winter months. They won't flower indoors but will hopefully survive and bloom again next season. The paper flower should be trimmed back in the fall and placed in a cool location for the winter. Keep the plant dry during this resting period. In March, bring the plant to a warmer location and begin watering. Though a challenge to get to rebloom, the effort is worth it. Treat the glory bower in a similar manner. The cool temperatures and dry conditions give plants the rest period they need to rebloom. The dipladenia or mandevilla also requires dry conditions during the winter. However, it does not need as cool of temperatures as the previously mentioned plants. Keep at a minimum of 55 F.
Before bringing plants indoors for the winter, make sure plants are healthy and insect free. Acclimate plants to their indoor environment well in advance of cool temperatures. Though frost may take the majority of our annual color, some can be brought indoors to brighten our winter months.
This article originally appeared in the November 8, 1996 issue, p. 168.